torque - basic start on a Bridgeport ( was Re: Some basic questions...

Hi Peter, list,

(I hope you guys change the subject line)


You have brought up 5 very different topics.

Torque needed is a simple calculation.

SEE : Message 45509 - mariss92705 - Date: Sat Jun 1, 2002 1:25 pm
Subject: Re: Newbie question: Motor sizing

A good place to start is to ask "how fast do I want it to go and how
much "push" do I need at that speed?" Use IPM (inches / min) and lbs
for "push".

(1) Watts = IPM times Lbs / 531

Use your answer (Watts) to size your motor.

0 to 100W, use a size 23 step motor.
100 to 200W, use a size 34 step motor.
200W or more, think about servos instead of steppers


There is a LOT more on that post, VERY worthwhile reading.

Dave

--- In CAD_CAM_EDM_DRO@y..., "Peter Moreton" <peter@r...> wrote:
> Hi,
>
> I'm starting down the CNC route, and would like to ask some
questions
> regarding my plans, before I make too many mistakes! If I list out
the
> salient points below, perhaps lister's could comment upon my
thinking...
>
> 1. I have acquired 3 large stepper motors, they are 'Oriental Motor
> VEXTA' devices, model number 3056-9412, rated at 2.9V / 3.3A and
are 1.8
> deg/step. Size wise, they have 70mm mounting centres and are 63mm
deep.
> A bit small , I know, but I'm not looking for speed. Probably about
300
> oz/inch?. Question, The steppers are marked as '2-phase'. Could
> anyone explain to me the significance of this?
>
> 2. I have a Bridgeport series-1 mill, in good condition. Do I really
> *need* to buy zero backlash leadscrews, or will the CNC controller
> software be able to calibrate out the backlash in the existing
> leadscrews?.
>
> 3. On the topic of the Bridgeport, does anyone have a view on how
best
> to make the mechanical connection from the stepper to the X,Y,Z
axis. I
> am expecting to use a toothed belt system, and wonder if there are
any
> commercial kits of parts to simplify the attachment of the steppers?
>
> 4. I have not yet purchased stepper driver boards, Gecko's would be
> nice, however I would like to use the cheaper Xylotex board instead,
> even though it cannot drive the steppers I have at full power.
>
> 5. Software wise, I was planning to use the BDI (Brain Dead Install)
> version of EMC on an old PC, and AutoCAD for drawing generation.
>
> Thanks for all input, Peter Moreton